|caseless system (n.)|
|Coiner||Villa from The Infinite Ikea|
A caseless system is a system that does not use any form of communication methods specifically made for systems (i.e PluralKit, Tupperbox, Simply Plural, etc). They may use other methods to display system information, like changing their nickname in a server to show who is fronting, or leaving signatures in messages, but this does not have to be the case.
The term name comes from the idea of a phone case. It is beneficial to have one for a phone, but it isn't necessary nor does it make the phone any less functional. The same concept can apply to caseless systems, as their lack of common communication methods commonly used by plurals doesn't make their system less valid.